It seems to be the device that is giving me grief with the engine starts. Looking specifically for a wiring diagram for it or an alternate solution. It is the device connected to the skinner valves and I think is controlling the throttle stop and high idle.Thanks All.

IIRC that is a 1980's technology that sucked when it was new and still does.The old straight temp and oil sending units workrd for ever and still do.I quit working for an outfit that brought me a big box full of those to install on a fleet of stationary Detroits that were being used on tunnel work. The company thought they would make the Mine Safety inspectors happy....dumb.

I know people don't like these, but if anyone ever upgrades to a 4 stroke with electronics they pretty much all have shutdowns built into the ECU. Some of the buses one can override the shutdown with a switch to get off the road.

a simple overheat shutdown is the only way to protect your investment.by the time your alarm sounds you can have done $1000's of dollars in damage...I would rather shut down in the middle of interstate 45 in downtown Houston than try and get out of traffic while an alarm is blaring and my motor is melting.My over-temp shut down has saved me twice in 10 years.once near williams AZ and the other in NM.in the summer with 3 digit ambient temps....

When I was a younger man, I am confident that there would not have been thirty seconds passed that I had not scanned the instruments and mirrors. I am simply not that good a driver these days and I know it. I can use all the help I can get, and system alarms are just a part of that.

I know the opinions on this are split. I chose to get rid of ALL original wiring, including the shutdown circuit. A 57 year old wiring system is not only unreliable, but dangerous. About 80% of the original wiring is unnecessary - air conditioning, passenger lighting, call system, etc. When I looked at the wiring diagram for the shutdown system, it appeared too complex to be reliable. The default for failure of a component in this circuit is engine shutdown - most of the time. A faulty temperature sending unit will not shut the engine down. I prefer to be the engine protection system. All critical monitoring is redundant on mt bus. I have a water temp gauge from one sending unit plus a telltale sending unit set at 190 degrees. If my gauge says 190 and the telltale agrees, it's time to take action. Same with oil pressure, etc. Today's electronics are far more reliable than the old electro-mechanical circuits from the 50's and 60's, but even these are not fail-safe. I can see the value of these systems for unattended gensets, but if you've got all the information right in front of you and redundant, I'd rather be the monitor, than be sitting on the side of the road trying to figure out where the engine shutdown circuit failure is.

Nothing beats a gauge and good eyes when a old DD shuts downs most of time it to late without water circulating they just set and cook they can reach over 250 degrees after shutdown there goes the heads without water to cool down the 1200 degrees the combustion reaches

GM's are the worst they always crack the top head never the lower that is easy to replace lol

There is a VERY big difference between an alarm system, and an auto shut down.

The auto shut down is there to protect the equipment from an IDIOT hired driver, who will just keep driving once the dashboard lights have lit up and the alarms are sounding. If it wasn't true, why would anyone have invented the shut down in the first place?

The older ones were brutish, and leave the driver little choice, the modern electronic ones give the driver a chance to act. My comments are related to the old style ones.

If a busnut who owns and pays for the equipment isn't smart enough to heed the warnings of the alarms, well, natural selection will take its course.

If your coach does not warn you before the auto shut down engages, then FIX or MODIFY it so that it will.

Your engine is not going to grenade in the next 10 seconds just because the temp has reached the alarmstat limits, which is the usual suspect. Loss of oil pressure is misadventure and/or poor maintenance.

The engine still turns once the auto shut down engages, and if you do something foolish like shift to neutral to make it stop turning, you lose the power steering as well.

So, with the cursed thing disconnected, the alarms sound, you get a surprise, you look at the dash, compare what you see with what you were doing to the coach and make some decisions. Maybe just slow down and gear down, you're pushing it too hard climbing the hill. Increased water flow and fan speed, decreased load, alarm goes out in 25 seconds as engine temp drops below the threshold. Or, if you want, you look for a way to get off the road, you reduce the demands being put on the engine, and get to a safe stopping spot of your choosing, with the coach operating as you expect it.

Compare that to an auto-shut down event: Wham, alarms, lights and no engine running. PANIC. Losing speed. In order to get the engine back, auto shut down requires you to do extra things that you haven't practiced, push some button, can't remember exactly, traffic whizzing by, can't get over, speed dropping, horns blaring, tractor trailer almost clips your mirror, haven't tested its proper functioning, don't know how to test its proper functioning, under the stress of alarms buzzing, and the trump card, it's your spouse driving, not you... and rolling to a stop in a travel lane on a twisty mountain climb with a shoulder only a tantalizing 50 feet further ahead?

Or, if it really goes wrong, have you ever considered trying to open the door with a live traffic lane to your right?

Lights and alarms, all confirmed and tested for function, wiring and alarmstats upgraded during my ownership, are all I would like, thank you, its my engine.

I already have to pay for the consequences of bus ownership, this is no different?

My 05 has a warning system on it ( I think it is essex or something like that I would go out in the shop and look but we are in the middle of a bad snow storm). When I first started to drive the bus and all components were new I drove with one eye on the gauges and one eye on the road. The bus now has over 100,000 miles on it and it has never broken down ( knock on wood). I find my self driving for hours not looking at the gauges as I have become complacent. I now am one of the idiot drivers and glad I have the system to warn me if something is going wrong.